Anacardic acid analogs have been tested as inhibitors of prostacyclin (PGI2) induced cyclic AMP synthesis in human platelets as well as on their molluscicidal action against B. glabrata. Triene analog of anacardic acid was found to be more potent than diene and monoene analogs in both platelets and snails. The decarboxylated derivative of anacardic acids and salicylic acid were inactive as molluscicides. It appears that both salicylic acid and the unsaturated side chain plays an important role for the biological action of anacardic acids.